In the electronic industry, protective clothing is used to separate human body from the clean room for production. As the wearer moves his or her arms and legs, electrostatic charge can be accumulated on the clothing. The accumulated electrostatic charge can be imparted to semiconductor devices, which would result in the electrostatic discharge (ESD) damage. Therefore, the protective clothing used should have antistatic effect or ESD protection effect.
Generally, the protective clothing with antistatic effect is manufactured by incorporating conductive yarn into antistatic fabric. The conductive yarn is usually composed of filaments having a conductive core or shell containing carbon black or graphite or conductive metal, filaments of metallic fiber, or filaments coated with conductive material.
The antistatic fabric mentioned above is known from the art that clothing made from the antistatic fabric does not have good permeability for wearing since the fibers are woven in dense structure in order to provide sufficient antistatic effect.
To solve the above problem, Taiwan Patent No. I232248 (also published as German Patent No. DE 19934442 A1) provides a non-woven material and a fabrication thereof, wherein the antistatic effect is achieved by blending carbon black or graphite into the polymer material. However, it is known from the art that directly blending carbon black into the polymer will result in embrittlement issue of the material, which leads to the process problem.
Furthermore, U.S. Pat. No. 6,451,427B1 discloses a fiber containing bamboo charcoal powder. Although the bamboo charcoal is superior in deodorization and hygroscopicity, it is difficult to keep color substantially uniform since the particle diameter is relatively large. Making the particle diameter small is desirable, but in that case, said deodorization and hygroscopicity effects will decrease. Thus, by blending fine particle diameter of carbon black, it will be possible to achieve the deodorization and hygroscopicity effects and keep color substantially uniform. However, the conductivity issue was not mentioned in U.S. Pat. No. 6,451,427B1. Particularly, the specific ratio of the bamboo charcoal with respect to carbon black for achieving necessary antistatic effect was not disclosed.
Thus, a requirement still remains for a multifunctional antistatic non-woven fabric material with multiple functions of having appropriate mechanical process and having antistatic, deodorization and hygroscopicity effects.
Solutions to these problems have been long sought but prior developments have not taught or suggested any solutions and, thus, solutions to these problems have long eluded those skilled in the art.